View Full Version : miller welder wiring question
02-17-2004, 05:33 PM
I just received a miller model srh-222 3 phase dc stick welder.A friend of mine upgrade his welders in his shop and gave me this one to use instead of running a gas powered machine.My problem is that I do not have 3 phase service and was wondering if this model can be wired to run on single phase.I know nothing about wiring welders and electrical work in general and any info would be helpful before I hire an electrician
you can make a phase converter, there instructions on this web pag or hobart web page. Rgards Jim
02-17-2004, 08:52 PM
If you post the s number and the rest of the nameplate information, I might be able to answer the question if the Miller site has the information.
02-18-2004, 09:37 AM
I did a search and couldnt find anything on a phase converter. Anyone help ? Also is this a big complicated process. Ive got a chance to score an awesome Lincoln mig real cheap. but its three phase...
02-18-2004, 10:54 AM
Phase converters are easy to build if you have an understanding of electrical power, phase balancing etc.
Here's a sight over on the Pratical Machinist that has good info
I build converters for three phase pumps for sewage lift stations, in neighborhoods where three phase power isn't available. I also built one for the "Magic Garage" for my old South Bend lathe.
the lathe has a 1hp motor. I used a 5 hp motor for an idler, to generate the third leg. I used a 5hp, because I had an old one, I replaced bearings on. And some day I want to get a 2 or 3 HP Bridgeport. I use capaciters and a time delay relay to provide starting for my idler. you need about 100mFD per HP to start a motor. I also have balancing capaciters between phases to balance my load. here's photo's of the Magic Garage three phase panel.
Here's the panal with input, and output fused disconnects.
02-18-2004, 11:00 AM
Here's the interior showing the cap's, relays,and contactors.
02-18-2004, 11:26 AM
So wait, phase converters WILL allow someone to use a 3-phase welder? My understanding (limited) was that it (phase convertors) worked fine for machinery using 3-phase motors.
But that welders power needs yeilded poor results, using phase convertors-not true?
02-18-2004, 11:57 AM
The schematic for this machine is on Miller's web site, and it appears to have internal jumpers for all 3 phases.
If you could get to the jumpers, and reconfigure them, all 3 transformers could be paralelled, and the machine would then run on single phase. How accessable those jumpers are is the question.
If you can't get to the jumpers, a rotary converter would work, provided it is large enough.
I have a Hobart 3 phase power supply we run with a wire feeder, and we have run it on the converter. The machine appears to run fine, BUT, we do limit it's duty cycle. Metering the artificial phase did indicate there was an imbalance of current going to that transformer.
02-18-2004, 12:11 PM
If you can run it "serated on single phase, besure to check the schematics and pick up the right leg so that you have 120 volt for the control circuits. Also check if the cooling fan is 3 phase, you might have to replace it with a single phase fan.
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